1. Field of the Invention
This patent specification relates to a method and apparatus for image forming, and more particularly to a method and apparatus for image forming capable of effectively performing a color image position adjustment.
2. Description of Related Art
Conventionally, color image forming apparatus that form a color image using a number of different color toners often cause a defective phenomenon that images of different color toners are displaced relative to each other. This typically causes a blurred color image. Therefore, these color image forming apparatus are required to adjust positions of color images to precisely form a single color image with an appropriate color reproduction.
Japanese Patent No. 2573855, for example, describes an exemplary color position adjustment and a test pattern used in the color position adjustment. Also, several other test patterns are described in published Japanese unexamined patent applications No. 11-65208, No. 11-102098, No. 11-249380, and No. 2000-112205. In the image forming apparatus disclosed in these documents, a plurality of photosensitive drums form a predetermined test image pattern using a plurality of color toners on both longitudinal sides of an image carrying surface of an image carrying member. The predetermined test pattern is detected by a pair of optical sensors. Based on this detection, displacements of the color images relative to each other are calculated and are used to justify the positions of the color images. More specifically, the predetermined test pattern includes a plurality of marks and the reading of the marks allows an analysis of a displacement of each color from a predetermined reference position. For example, the color position adjustment calculates a displacement dy in a sub-scanning direction y, a displacement dx in a main scanning direction x, a displacement dLx of an effective line length in a main scanning line, and a skew dSq in the main scanning line.
Particularly, the above-mentioned Japanese patent No. 2573855 describes an image forming apparatus capable of moving a reflective mirror arranged on a light path with a stepping motor to adjust a magnification, a slant in the sub-scanning direction, and a parallel movement so as to correct a registration. Also, this image forming apparatus is capable of controlling a drive of a photosensitive drum or a transfer belt to correct a registration.
However, the above-mentioned color position adjustment is not automatically performed by the image forming apparatus. The present inventors have recognized that at present there is no such image forming apparatus that can automatically perform a color position adjustment operation.
This patent specification describes a novel method of image forming. In one example, this novel method includes the steps of providing, detecting, and performing. The providing step provides a plurality of detachable image forming mechanisms for forming color images, each individually using a color toner different from each other, and an image carrying member for carrying the color images sequentially overlaid on one another into a single color image. The detecting step detects an individual exchange of the plurality of detachable image forming mechanisms. The performing step performs an adjustment for eliminating displacements of color images formed by the plurality of detachable image forming mechanisms, in accordance with a detection of the individual exchange of the plurality of detachable image forming mechanisms detected in the detecting step.
In the above-mentioned method, each of the plurality of detachable image forming mechanisms may include a photosensitive member and a developing mechanism containing a different developing agent.
The above-mentioned method may further include the step of executing a process control for controlling image forming parameters prior to the performing step.
This patent specification further describes a novel image forming apparatus. In one example this novel image forming apparatus includes an optical writing mechanism, a plurality of detachable image forming mechanisms, an image carrying member, an exchange detecting mechanism, a test pattern reading mechanism, and a controlling mechanism. The optical writing mechanism is arranged and configured to generate a writing beam modulated according to image data. Each of the plurality of detachable image forming mechanisms includes a photosensitive member and is arranged and configured to form a color image with a different color toner in accordance with the writing beam. The image carrying member carries color images formed by the plurality of detachable image forming mechanisms and that are sequentially overlaid on one another into a single color image. The exchange detecting mechanism is arranged and configured to detect an individual exchange of the plurality of detachable image forming mechanisms. The test pattern reading mechanism is arranged and configured to read a predetermined test pattern formed by the plurality of detachable image forming mechanisms on the image carrying member. The controlling mechanism is arranged and configured to instruct the plurality of detachable image forming mechanisms to form the predetermined test pattern on the image carrying member when the exchange detecting mechanism detects an individual exchange of the plurality of detachable image forming mechanisms. The controlling mechanism is further arranged and configured to perform a color image position adjustment based on readings of the predetermined test pattern by the test pattern reading mechanism.
The exchange detecting mechanism may include a detecting member for the apparatus and an actuator for each of the plurality of detachable image forming mechanisms. The detecting member may detect the actuator that is moved to a position detectable by the detecting member after a corresponding one of the plurality of detachable image forming mechanisms is driven.
Each of the plurality of detachable image forming mechanisms may use one of a magenta, cyan, yellow, and black color toners different from each other.
The predetermined test pattern may include patterns of the magenta, cyan, yellow, and black color toners to be sequentially formed with a slight distance between two immediately adjacent patterns.
The color image position adjustment may adjust the optical writing mechanism to justify positions of the color images formed on the image carrying member via the plurality of detachable image forming mechanisms.
This patent specification further describes a novel method of image forming. In one example, this novel method includes the steps of arranging, providing, detecting, instructing, reading, and performing. The arranging step arranges an optical writing mechanism to generate a writing beam in accordance with image data. The providing step provides a plurality of detachable image forming mechanisms detachably installed to an apparatus. The plurality of image forming mechanisms are capable of forming color images according to the writing beam with different color toners in a manner overlaying on one after another to form a single color image on an image carrying member. The detecting step detects with a uniquely arranged detecting mechanism an event that at least one of the plurality of detachable image forming mechanisms is exchanged. The instructing step instructs the plurality of detachable image forming mechanisms to form a predetermined test pattern on the image carrying member when the detecting step detects the event that at least one of the plurality of detachable image forming mechanisms is exchanged. The reading step reads the predetermined test pattern formed by the plurality of detachable image forming mechanisms on the image carrying member. The performing step performs a color image position adjustment based on the readings of the predetermined test pattern in the reading step.
The uniquely arranged detecting mechanism used in the detecting step may include a detecting member disposed to the apparatus and an actuator disposed to each of the plurality of detachable image forming mechanisms. The detecting member detects the actuator that is moved to a position detectable by the detecting member after a corresponding one of the plurality of detachable image forming mechanisms is driven.
Each of the plurality of detachable image forming mechanisms may use one of a magenta, cyan, yellow, and black color toners different from each other.
The predetermined test pattern may include patterns of the magenta, cyan, yellow, and black color toners to be sequentially formed with a slight distance between two immediately adjacent patterns.
The color image position adjustment may adjust the optical writing mechanism to justify positions of the color images formed on the image carrying member via the plurality of detachable image forming mechanisms.